Excessive Rain threat

Lower Ohio River Valley and just south.

Current Day 1 Forecast

Day 1 Threat Area in Text Format  

Current Day 2 Forecast

Day 3 forecast below

Severe Storm Risk.

New strong system this week in the Midwest, then East/Northeast.

https://www.spc.noaa.gov/products/outlook/

Current Day 1 Outlook
Current Day 2 Outlook
Current Day 3 Outlook
Current Day 4-8 Outlook

High Temperatures today and Monday:

 Pleasant Midwest/Northeast. Heat Southwest........some of which spews into the Central High Plains.  

Highs days 3-7.

 Very warm to hot in the Southeast but chilly to cold air N. Rockies to N. Plains tries to expand southeast...........at times.    CDD's from heat still in the southeast. But most significant HDD's of the season in the north. This is what rallied natural gas last week.

Surface features for the same 3-7 day period:

Initially strong cold fronts coming from Canada, moving southeast and stalling/dying (as they encounter a stout upper level ridge), that trigger rains.......more rain as they encounter higher moisture and slow down. 

Dew points.

 70+ on this scale makes it feel uncomfortable(sticky air)!  

Higher dew points have been suppressed to the south. Much drier air in the Plains/Midwest/Northeast.

Heat Index:

Heat and high humidity COMBINED. Feels like temperature.  Will feel hotter from humidity in the southeastern sector.

Current Surface features:

Strongest cold front of the season has bogged down!!!  Waves along the front dumping rains.

New, much stronger system with its cold front will be organizing in the Northern Plains. This will  steal the show this week.

https://weather.com/maps/currentusweather

Latest radar loops.

http://www.nws.noaa.gov/radar_tab.php

Satellite picture.

Distinctive band of clouds from the East Coast, back west. Here comes the new strong system, now forming in the N.Plains/N.Rockies.  

Rains the past 24 hours.  

Along the stalling front...........Ohio Valley and just south/west.

You can go to this link to see rain totals from recent time periods:

https://water.weather.gov/precip/

Go to precipitation, then scroll down to pick a time frame. Hit states to get the borders to see locations better. Under products, you can hit "observed" or "Percent of normal"

Soil moisture anomaly:

Too wet in a large area from one of our wettest Septembers!  

The 2nd map gets updated once a week and is due to be updated.

Rains compared to average for the last 7, 14, 30 and 60 days. 

Usually not updated for previous day until late the next day.

Note how wet it's been over the past 60 days over eastern 2/3rds of the country!

https://www.atmos.illinois.edu/~snodgrss/Ag_Wx.html

Drought Monitor.

This product is updated every Thursday. This measure takes into account the long term precip/sub soil moisture and goes back over MANY months. Top map is last Thursday. Map below it was the previoust week.

Drought in the West. Recent heavy rains made another dent in the Texas drought, which will show up this Thursday.

            http://droughtmonitor.unl.edu/Maps/CompareTwoWeeks.aspx   

Temperature Anomalies from GFS ensembles(fairly reliable product) going out 2 weeks. These maps show the Northern Hemisphere. The map of the US is front center. Look for the state borders in  white.

Today/Tomorrow:  New cold surge in the Northwest will be part of a strong system developing now and taking aim downstream/southeast..............warm slug of air ahead of it.  

In 5+ days:

 Huge battle of the air masses!!! Max cold anomalies converging close to the max warm anomalies. Slight changes in the forecast features can result in a 25 deg. temperature change for places close to the zone with the most extreme temperature differential.

In 10+ days:

 Chilly blast that was predicted earlier looks to encouter more resistance headed southeast! How deeply can it penetrate south as it encounters stronger resistance from an upper level ridge in the Southeast?

Day 15:  Warm anomalies far Northwestern Canada.....cool downstream. How far southeast will the real chilly air be?  Friday's models undercut the cold with a strong jet stream and even try to rebuild the heat ridge in the South/Southeast. Some of Saturday's models stay on that warmer track...great uncertainty. Sundays' models continue to be split on this. We will have a strong northern stream from Canada vs the heat ridge building in the Southeast during week 2.

The top map is the Canadian ensemble average, the maps below are the individual members that make up the average

End of week 2....................0Z ensembles from Sunday. There will be a deep upper level low/trough in Canada with widespread cold extending south into the northern parts of the US. There will be a strong upper level ridge in the Southeast US. How dominant either of those EXTREME features becomes, will determine the weather in between!!  
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Each member is like the parent, Canadian model operational model.......with a slight tweek/variation in parameters. Since we know the equations to represent the physics of the atmosphere in the models are not perfect, its useful to vary some of the equations that are uncertain(can make a difference) to see if it effects the outcome and how.

The average of all these variations(ensembles) often yields a better tool for forecasting. It's always more consistent. The individual operational model, like each individual ensemble member can vary greatly from run to run.........and represent an extreme end of the spectrum at times. The ensemble average of all the members, because it averages the extremes.............from opposite ends of the spectrum............changes much less from run to run.

360h GZ 500 forecast valid on Oct 08, 2018 00 UTC

The low skill, longer range CFS model for weeks 3-4.

This is one of the few times we can look at this product and say........WOW!  Extreme Upper level ridging Alaska to West Coast.  The most extreme blue/cold anamolies downstream for all of Canada, crossing the US border into the Plains/Upper Midwest.............with a very sharp cut off, going southeast...........where they turn into warm brown anamolies.

The actual pattern is moderate/high confidence for this time frame.............but where it sets up will be a huge question mark in the days ahead............that can make a 20+ degree temperature difference in the forecast for the area in the zones near the outside of the extreme temperature departures. 

As shown below, this would be a WET pattern for the Midwest and points south.

Heating degree days(from cold weather) are replacing cooling degree days(from hot weather) as being the most important as we get into October.

Check in tomorrow to read something different............."low skill" (-:

Precip below:

National Weather Service 6-10 day, 8-14 day outlooks. Automated on weekends

 As we turn the calendar page to October, very chilly air from Canada pouring into the Northcentral US with an upper level trough...........but at the same time unseasonable warmth in the Southeast as the heat ridge builds back again. Those 2 features will have a massive battle on weather models in the week 2 period.

This is the recipe for  wet weather!  Not good for harvest.

Temperature Probability

Precipitation Probability

the 8-14 day outlooks ArchivesAnalogsLines-Only FormatGIS Data

Temperature Probability

Precipitation Probability

The last 12z GFS operational model was MUCH colder at day 10. Allowing the cold Canadian model to blast deeply south......but this is just one solution!

gfs_namer_240_200_wnd_ht	gfs_namer_240_500_vort_ht
gfs_namer_240_1000_500_thick	gfs_namer_240_850_temp_ht

The just out 12z European operational model has the complete opposite going on at day 10. Instead of cold surging south, it has warmth surging north in same areas............eastern 1/2 of the country. Could be that the GFS is just faster with the cold surge?

Thanks for the analysis Mike.

YW Jim!